1. Field of the Invention
The present invention relates generally to disinfection techniques and methods of treating water or aqueous solution for the removal of microorganisms therefrom, and particularly to a method of removing Escherichia coli (E. coli) bacteria from an aqueous solution using carbon nanotubes functionalized with a dodecylamine group (C12H27N).
2. Description of the Related Art
Escherichia coli (commonly abbreviated E. coli) is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms). Most E. coli strains are harmless, but some, such as serotype O157:H7, can cause serious food poisoning in humans, and are occasionally responsible for product recalls. The harmless strains are part of the normal flora of the gut, and can benefit their hosts by producing vitamin K2 and by preventing the establishment of pathogenic bacteria within the intestine.
Certain strains of E. coli, such as O157:H7, O121 and O104:H21, produce potentially lethal toxins. Food poisoning caused by E. coli is usually caused by eating unwashed vegetables or undercooked meat. O157:H7 is also notorious for causing serious and even life-threatening complications, such as haemolytic-uremic syndrome. This particular strain is linked to the 2006 United States E. coli outbreak due to fresh spinach. Severity of the illness varies considerably. It can be fatal, particularly to young children, the elderly, or the immuno compromised, but is more often mild.
If E. coli bacteria escape the intestinal tract through a perforation (for example from an ulcer, a ruptured appendix, or due to a surgical error) and enter the abdomen, they usually cause peritonitis that can be fatal without prompt treatment. However, E. coli are extremely sensitive to such antibiotics as streptomycin or gentamicin. This, however, could easily change, since E. coli quickly acquires drug resistance. Recent research suggests that treatment with antibiotics does not improve the outcome of the disease, and may, in fact, significantly increase the chance of developing haemolytic-uremic syndrome.
Intestinal mucosa-associated E. coli are also observed in increased numbers in the inflammatory bowel diseases, Crohn's disease, and ulcerative colitis. Invasive strains of E. coli exist in high numbers in the inflamed tissue, and the number of bacteria in the inflamed regions correlates to the severity of the bowel inflammation.
Resistance to beta-lactam antibiotics has become a particular problem in recent decades, as strains of bacteria that produce extended-spectrum beta-lactamases have become more common. These beta-lactamase enzymes make many, if not all, of the penicillins and cephalosporins ineffective as therapy. Extended-spectrum beta-lactamase-producing E. coli are highly resistant to an array of antibiotics, and infections by these strains are difficult to treat. In many instances, only two oral antibiotics and a very limited group of intravenous antibiotics remain effective. In 2009, a gene called New Delhi metallo-beta-lactamase (shortened as NDM-1) that even gives resistance to intravenous antibiotic carbapenem was discovered in India and Pakistan in E. coli bacteria.
Due to the severe nature of E. coli infection and the potential for lethality, it is necessary to develop alternative treatments for E. coli infection and for removal of E. coli bacteria from water and foods. Thus, a method of removing Escherichia coli (E. coli) bacteria from an aqueous solution solving the aforementioned problems is desired.